A Philadelphia lawyer with a business clientele, Trachtman subscribes to a 90/10 rule, i.e., 10 percent of the law covers about 90 percent of the legal problems corporate executives are likely to encounter. In this convenient context, he offers a lucid brief that focuses on the ins and outs of contract law. By definition, a contract is simply a legally binding agreement that comprises an unequivocal offer and an unconditional acceptance. Owing to the adversarial nature of the US legal system and an abundance of case law, Trachtman makes clear, there's more to even a handshake deal than a layman might suspect. For one thing, whichever party makes the offer that's accepted gains the upper hand. For another, equity and intent are largely irrelevant; what counts is knowing the rules and following them. ""In contract law, words are like weapons,"" Trachtman warns. ""Make sure you know which way the gun is pointed before you decide to pull the trigger."" Documents, he notes later, are the ultimate weapons, especially in cases where the enforceability of an oral agreement is at issue. While laying a paper trail can prove helpful, the author cautions that forms with boilerplate exceptions to hold-harmless provisions, merger clauses, reliance doctrine, and related contractual terms may not protect either buyers or sellers. The verdict: a lively and enlightening guide for executives anxious to keep their legal liabilities to a minimum.